Deciphering a SOAP fault with a 400 status code

Recently working with a partner I came across a solution for a limitation in WCF error handling.  The root of the issue is a difference between SOAP 1.1 and SOAP 1.2 in the allowed HTTP status codes when a SOAP fault is returned.  For SOAP 1.1, the status code must be 500 “Internal Server Error”.  For SOAP 1.2, it varies based on the type of the SOAP fault.  For env:Sender, the status code is 400